Dump truck



Dec. 10, 1957 H. c. HARBERS arm, 2,815,930

DUMP TRUCK Filed Sept. 13, 1954 4 Sheets-Sheet 1 v INVENTOR 6 N HENRY 6.HARBER$ DONALD R. MEROHAN T LL Q ATTORNEY Dec. 10, 1957 H. c. HARBERSETAL DUMP TRUCK Filed Sept. 13, 1954 v 4 Sheets-Sheet 4 INVENTOR HEN Y6.'HARBER? DOMLD R.- MERCHANT ATTORNEY United States Patent DUMP TRUCKHenry C. Harbors, Pasadena, and Donald R. Merchant, Glendale, Calif.,assignors to Cook Bros. Equipment Co., Los Angeles, Calif., acorporation of California Application September 13, 1954, Serial No.455,718

12 Claims. (Cl. 298-14) Our invention relates to dump trucks of thesemitrailer type, and of the character disclosed in our copendingapplication Serial No. 445,296, filed July 23, I954, wherein is embodieda power-driven vehicle including a front wheel assembly, and asemi-trailer including a rear wheel assembly, the two assembliesnormally supporting a dump body in load-carrying position, and 'asemi-trailer having a supporting frame to which the dump body is fixedbut which is separate from the front wheel assembly and mounted on therear wheel assembly for upward and rearward swinging movement to elevatethe body to dumping position, and a hoisting mechanism operable to soswing the frame by effecting relative approaching movement of the wheelassemblies.

It is a purpose of our present invention to provide a dump truck inwhich the dump body is mounted for rolling movement longitudinally onthe supporting frame of the trailer so that when the frame is swungupwardly and re'arwardly by a hoisting mechanism, the bodysimultaneously rolls rearwardly downward on the frame to a dumpingposition. Thus the height of the center of gravity of the dump body fromthe ground during the hoisting operation does not rise to as high aposition as that of a dump body which is fixed to the supporting frame,and therefore greater stability is attained to minimize the possibilityof overturning during a dumping operation. Moreover, by maintaining alower center of gravity less power is required by the hoisting mechanismto elevate a loaded body to dumping position.

It is also a purpose of our invention to provide a dump truck in whichthe dump body is relatively short as compared to the length of thetrailer, made possible by mounting the dump body for rolling movement onthe supporting frame of the trailer. Since the trailer is longer thanthe dump body, the overall wheel base of the truck,

that is, the distance from the front axle of the truck to I the rearaxle of the trailer, makes it possible to classify the vehicle in ahigher gross vehicle weight rating in accordance with local and Stateload restrictions, and, as a consequence, a greater pay load can becarried. Moreover, through use of a dump body relatively short ascompared to the length of the trailer the stability of the truck whenthe dump body is elevated is furthered.

Another purpose of our invention is the provision of a semi-trailer dumptruck of this character having a control means which functions toinitiate rearward rolling movement of the dump body as the supportingframe of the trailer is hoisted to elevated position, to controlmovement of the body during this dumping operation, and to return thebody to its original position on the supporting frame when the latter islowered. Adjusting means is provided for this control means by which itis possible to locate the body on the supporting frame to attain properload distribution on the truck axles and thus comply with the highwayaxle loading restrictions. It also governs the height of the rear edgeof the body when in dumping position, as well as its clearance withrespect to the tires of the rear wheel assembly.

Patented Dec. 10, 1957 It is a further purpose of our invention toprovide in a dump truck of this type latching mechanism for the tailgate of the dump body which is operable to latch or release the tailgate according as the dump body is moved on the supporting frame toload-carrying position or load-dumping position.

We will describe only one form of dump truck embodying our invention,including one form of tail gate latch and releasing mechanism, and willthen point out the novel features thereof in claims.

In the accompanying drawings:

Fig. l is a view showing in side elevation one form of dump truckembodying our invention wherein the dump body is in load-carryingposition.

Fig. 2 is a view similar to Fig. 1 showing the dump truck in dumpingposition.

Fig. 3 is an enlarged vertical sectional view taken on the line 3-3 ofFig. 1.

Fig. 4 is an enlarged sectional view taken on the line 44 of Fig. 6 andshowing the tail gate latching and releasing mechanism in its movementto gate releasing position.

Fig. 5 is a view similar to Fig. 4 showing the mechanism in its movementfrom gate releasing position.

Fig. 6 is an enlarged vertical sectional view taken on the line 66 ofFig. 4.

Fig. 7 is an enlarged sectional view taken on the line 7-7 of Fig. 5.

Fig. 8 is a vertical sectional view taken on the line 8-8 of Fig. 3.

Fig. 9 is an enlarged detailed perspective view of one of the couplingbrackets shown in Fig. 1.

Referring more particularly to the drawings, the dump truck comprises arigid frame F including parallel side beams 15 connected together atlongitudinally spaced points by cross beams 16, and adjacent theirforward ends by an additional cross beam 17 of substantially 8- form incross section. Adjacent its rear end the frame F is supported by a rearwheel assembly A which is of the tandem axle type, the two axles 18 ofwhich support the ends of springs 19, with the springs carryingdepending bearings 20 in which trunnions 21 are mounted. The trunnionsare fixed to members 21a secured to the undersides of the beams 15. Thisarrangement of elements provides pivotal connection between the frameand the rear wheel assembly so that the frame may tilt upwardly andrearwardly about the trunnions 21 as a center.

Constituting a draft and lifting means for the frame F are a pair ofheavy duty links 22 which are pivoted at their rear ends on trunnions 23mounted in brackets 23a fixed to the outer sides of the beams 15 betweenthe ends thereof. These links 22 project forwardly beyond the forwardends of the beams 15 in any position of the two. At their forward endsthe links 22 are pivoted on trunnions 24 which project from oppositesides of a conventional form of fifth wheel 25 supported by a frontwheel assembly A-l which includes tandem axle rear wheels 26, sideframes 27 and a cross plate 28. This front wheel assembly is preferablythe rear portion of a self-powered vehicle commonly used in connectionwith semi-trailers such as is formed by the rear wheel assembly A andthe frame F.

The links 22, between the ends thereof, are formed with dependingextensions 29 which constitute wells connected at the bottoms thereof bya cross beam 30. To this cross beam a pair of hydraulic jacks J of themultiple telescopic type are pivoted at their lower ends as at 31, whiletheir upper ends are pivotally connected as at 32 to the cross beam 17.These jacks constitute means for hoisting the frame F to the elevatedposition shown in 3 Fig. 2, but it is to be understood that other meansthan the jacks could be provided for the purpose.

The draft links 22 are additionally rigidly connected one to the otherby cross beams 33, and a box beam 34 upon which latter the forward endsof the side beams rest when the frame F is in the lowered position shownin Fig. 1.

Supported for rolling movement longitudinally on the frame F is a dumpbody B which includes a pair of parallel beams 35 fixed to the underside of the bottom of the body between side beams 35a. To the beams 35frames 36 are secured at spaced intervals along the length thereof, andin each of which is journalled a flanged roller 37. These rollers aremovable on a track made up of a pair of rails 38 fixed to the top of theside beams 15 and coextensive in length therewith.

The rollers 37 are confined to rolling movement on the rails by brackets39 bolted to the outer sides of the beams 35 and arranged in pairsadjacent the opposite ends thereof. Each bracket is of the U-form shownin Fig. 9, to accommodate the respective roller 37 between the parallelportions thereof, and is formed with a depending inturned L-shaped lip40 which extends to the under side of the upper flange edge of therespective'side beam 15 with which it has sliding contact, and wherebythe roller is at all times held in rolling contact with the respectiverail.

To aid in transverse centering of the frame F on the links 22 as it ismoved to lowered position, a pair of guide plates 41 are fixed to theconfronting sides of the links so as to extend thereabove where they areformed with outwardly flared lips 41a. As the frame F is moved to thelowered position shown in Fig. 1 the lips 41a are engaged by thebrackets 39 thus causing them to be guided between the plates andthereby centering the frame on the links. It will be understood thatthis does not interfere with elevation of the frame F since the bracketscan slide out of engagement with the plates.

For controlling movement of the dump body B on the frame F as the latteris elevated to tilted position, as well as to return the dump body to asubstantially medial position with respect to the overall length of thetruck, and to a fore position on the frame F, a pair of control links 42are pivoted at their forward ends to the draft links 22 at the rear sideof the wells 29 as indicated at 43. The rear ends of these links 42 arepivoted to the side beams 35a of the dump body by pins 44 engageablewithin any one of a series of openings 45 in the side beams so as tomake such pivotal connection adjustable lengthwise with respect to thedump body. The purpose of this adjustable connection is to predeterminethe limits of movements of the dump body B on the frame F in bothdirections, and thus the position of the dump body on the frame when thelatter is lowered or elevated can be controlled. Moreover, the controllinks 42, under movement of the draft links 22, are operable to initiatedownward rolling movement of the dump body as the frame F is lifted toelevated position.

The dump body B is provided at its rear end with a tail gate T pivotedat its upper end as at 46 so as to gravitate to open or closed positionaccording as the body occupies tilted position or a substantiallyhorizontal position. T o automatically latch the gate T in closedposition, as well as to automatically release the gate so that materialmay be discharged from the body when tilted, a latching mechanism isprovided.

This latching mechanism comprises, in the present instance, a shaft 47journalled in the beams 35 (see Fig. 6) and in hangers 48 secured to thebody B. To oppo site ends of the shaft 47 crank arms 49 are fixed, andpivoted as at 50 to these arms are the forward ends of a pair of rods51. The rear ends of the rods are pivotally connected as at 52 to shanks53 of latch hooks 54, and the shanks are movable lengthwise throughsuitable openings in an end beam 55 of the dump body so that the hooksproject to the rear side thereof for movement into and out of engagementwith pins 56 on opposite edges of the gate T to secure the pins inkeepers 57 fixed to the beam, and thereby lock the gate in closedposition, or to release the pins so that the gate can gravitate to openposition.

On the left-hand end of the shaft 47 (as viewed in Fig. 6) and at theinner side of the adjacent hanger 48, is fixed an arm 58 provided with alateral extension 59 having on its free end a pin 60. To this pin isconnected the lower end of a coiled contractural spring 61 the lower endof such spring being connected to an ear 62 fixed to the adjacent beam35a. The spring 61 is for the purpose of maintaining the latch hooks 54in gate latching or releasing position once the latch mechanism isactuated to occupy the position shown in Fig. 4, or the position shownin Fig. 5.

This mechanism could be actuated manually by turning of the shaft 47,but it is preferred to actuate it automatically through movement of thebody B longitudinally on the frame F. To this end the shaft 47 has fixedthereto a lever 63 provided with a slot 64 in its free ends. A pin 65fixed to a plate 66'bolted to the outer side of one of the beams 15 ispositioned lengthwise of the beam so that the slotted end of the leverwill engage the pin under movement of the body B on the frame F to swingthe lever to the angular position shown in Fig. 4 when the body movesrearwardly on the frame, or to the opposite angular position shown inFig. 5 when the body is moved forwardly on the frame. In this angularposition of the lever it is to one side or the other of vertical deadcenter, and since the lever and the arms 58 are fixed to the shaft 47 atthe same point circumferentially thereof, the springs 61 operate tomaintain the lever in either angular position once it is moved to theright or to the left of dead center.

To insure lever 63 engaging pin 65 to properly operate the latchingmechanism, its angle, when the mechanism is in the position shown inFig. 4, can be varied by an adjustable stop S in the form of a screwthreaded in an ear 66a on that hanger 48 adjacent the lever, and whichscrew is positioned to limit movement of the arm 49 in acounter-clockwise direction, and hence the angle of the lever.

In order to insure proper operation of the latching mechanism and yetprevent breakage of any of its parts due to improper mounting oradjustment particularly in moving the rods 51 to the position shown inFig. 4, each rod is made in two sections 51a and 5117 connected at theirconfronting ends by a yieldable coupling K. This coupling comprises acylinder 67 closed and secured at one end to the rod section 51a. Theconfronting end of the rod section 51b is slidably received in thecylinder and provided with a head 68 for centering it therein. vA coiledexpansible spring 69 surrounds the rod section 51b between the head 68and one end of the cylinder, which operates to urge the confronting endsof the rodsections toward each other.

With the rod sections connected by this yieldable coupling K, it isapparent that the two sections are movable relatively to compensate forany improper adjustment of the mechanism, and yet insure movement of therods to either of'the two extreme positions for latching or releasingthe tail gate.

The operation of the dump truck is as follows:

In the load-carrying position of the truck shown in Fig. 1, the body Boccupies a position forwardly on the frame F where it is held againstmovement by the control links 42 through the draft links 22. The tailgate T is secured in closed position by the latch hooks 54 since themechanism for operating the latter is in the position shownin Fig. 4.

To dump the load from the body B the jacks J-are operated by supplyingfluid under pressure thereto from any suitable source (not shown) andthrough lines and valves of the chat-aster disclosed in our applicationhereinbefore referred to. Under such operation the jacks are extendedupwardly to exert a lifting force on the draft links 22, and since therear wheel assembly A is separate from the front wheel assembly Al, thetwo assemblies under such lifting force are caused to approach eachother. This allows the frame F and the links 22 to buckle upwardrelatively so that under continued extension of the jacks the frame andthe included body B are swung upwardly and rearwardly about thetrunnions 21 to the position shown in Fig. 2.

During this operation the control links 42 function to initiate downwardrolling movement of the body B on the frame F as well as to limit suchbody movement to the aft position shown in Fig. 2, wherein its lower endis disposed to the rear of the rear wheels of the assembly A. As thebody approaches this aft position the levers 63 are swung by the pins 65from the position shown in Fig. 4 to the position shown in Fig. 5,thereby causing the latching mechanism to move the latch hooks 54 out ofengagement with the gate pins 56 to release the gate T and, thus allowthe material to be dumped from the body.

Through adjustment of the pins 44 in the openings 45, the control linkscan be caused to regulate the height of the dumping end of the body-Bfrom the ground, as well as its position at the rear of the wheelassembly A to insure tire clearance.

Following the aforedescribed dumping operation the truck parts can berestored to the original positions shown in Fig. l by relieving thejacks J of pressure fluid which permits them to collapse, and by whichthe draft links 22, under the weight of the frame F and the body B, willbe forced downward causing the two wheel assemblies A and A1 to moveaway from each other and back to their original spaced position.

During this operation the control links 42 are actuated to pull and thusmove the body B forwardly on the frame F and back to its originalposition As the body moves to load-carrying position gravity acts toclose the gate T following which the levers 63 are swung by the pins 65to the position shown in Fig. 5, thereby operating the latch mechanismto move the latch hooks 54 so as to re engage the gate pins 56 and thussecure the gate in closed position.

As clearly illustrated in Fig. l, the dump body B is considerablyshorter than the combined length of the draft links 22 and the frame Pwhich actually constitute the trailer of the vehicle, and hence the bodycan be located midway between the ends of the trailer to attain properload distribution on the axles. This is made possible by the fact thatthe body is movable lengthwise on the frame F, coupled with theadjustable connection of the control links 42 with the frame beams tolocate the body on the trailer when in load-carrying position. Since thetrailer can be much longer than the body, the overall wheel base of thetruck as a unit makes it possible to classify the vehicle in a highergross vehicle Weight rating in accordance with local and staterestrictions, and consequently a greater pay load is achieved.

Because the dump body rolls rearwardly as it is elevated by the frame Fin a dumping operation, it does not rise to as high a position as thecenter of gravity of a fixed body does, and thus by maintaining a lowcenter of gravity less hydraulic pressure is required to be supplied tothe jacks J for elevating the loaded body. Moreover, because of this lowcenter of gravity coupled with the shorter body, greater stability isattained.

What we claim is:

l. A dump truck, including: a front wheel assembly; a rear wheelassembly; a frame separate from the front wheel assembly and pivoted onthe rear wheel assembly for vertical tilting movement from asubstantially horizontal position to an upwardly and rearwardly inclinedposition; draft means connecting the front wheel assembly to the frame;mechanism connectedbetween the frame and the draft means, and arrangedto exert a lifting force on the frame thereby causing operation of thedraft means to produce relative approaching movement of said wheelassemblies whereby the frame is swung to said inclined position; a dumpbody supported for movement longitudinally on the frame to occupy a foresubstantially horizontal position when the frame is in a correspondingposition, and an aft position when the frame is in the aforesaidinclined position; and means connected between the draft means and thedump body and operating under approaching movement of said wheelassemblies to limit the dump body to a predetermined aft position, andoperating under movement of said wheel assemblies away from each otherto restore the dump body to said fore position.

2. A dump truck, including: a front wheel assembly; a rear wheelassembly; a frame separate from the front wheel assembly and pivoted onthe rear wheel assembly for vertical tilting movement from asubstantially horizontal position to an upwardly and rearwardly inclinedposition; draft means connecting the front wheel assembly to the frame;hydraulic mechanism connected between the frame and the draft means, andarranged to exert a lifting force on the frame thereby causing operationof the draft means to produce relative approaching movement of saidwheel assemblies whereby the frame is swung to said inclined position; adump body supported for rolling movement longitudinally on the frame tooccupy a fore substantially horizontal position when the frame is in acorresponding position, and an aft position when the frame is in theaforesaid inclined position; and means connected between the draft meansand the dump body and operating under approaching movement of said wheelassemblies to limit the dump body to a predetermined aft position, andoperating under movement of said wheel assemblies away from each otherto restore the dump body to said fore position.

3. A dump truck, including: a front wheel assembly; a rear wheelassembly; a frame separate from the front wheel assembly and pivoted onthe rear wheel assembly for vertical tilting movement from asubstantially horizontal position to an upwardly and rearwardly inclinedposition; draft means connecting the front wheel assembly to the frame;hydraulic mechanism connected between the frame and the draft means, andarranged to exert a lifting force on the frame thereby causing operationof the draft means to produce relative approaching movement of saidwheel assemblies whereby the frame is swung to said inclined position; adump body supported for rolling movement longitudinally on the frame tooccupy a fore substantially horizontal position when the frame is in acorresponding position, and an aft position when the frame is in theaforesaid inclined position, the dump body being shorter than the wheelbase of the dump truck so that when it is in said fore position it issubstantially midway between the axles of said wheel assemblies; andmeans connected between the draft means and the dump body and operatingunder approaching movement of said Wheel assemblies to limit the dumpbody to a predetermined aft position, and operating under movement ofsaid wheel assemblies away from each other to restore the dump body tosaid fore position.

4. A dump truck, including: a front wheel assembly; a rear wheelassembly; a frame separate from the front wheel assembly and pivoted onthe rear wheel assembly for vertical tilting movement from asubstantially horizontal position to an upwardly and rearwardly inclinedposition; draft links pivoted at their forward ends to the front wheelassembly and pivoted at their rear ends to the frame; a dump bodysupported for movement longitudinally on the frame to occupy a foresubstantially horizontal position when the frame is in a correspondingposition, and an aft position when the frame is in the aforesaidinclined position; a pair of hydraulic jacks pivoted at one of theirendsto the frame and pivoted at their other ends to the draft links, saidjacks operating .toexert a lifting force on the frame thereby causingoperation of the draft links to produce relative approaching movement ofsaid wheel assemblies whereby the frame is swung to said inclinedposition; and control links pivoted at :their forward ends to the draftlinks and at their rear ends to the dump body, the control linksoperating under approaching movement of said wheel assemblies to moveand yet limit the dump body to a predetermined aft position, andoperating under movement of said wheel assemblies away from each otherto restore the dump body to said fore position.

5. A dump truck as embodied in claim 4 wherein means is provided forvarying the point of connection of the rear ends of the control linkslongitudinally on the dump body to vary the fore and aft positions ofthe dump body on the frame.

6. A dump truck, including: a front wheel assembly; va rear Wheelassembly; a frame separate from the front wheel assembly and pivoted onthe rear wheel assembly for vertical tilting movement from asubstantially horizontal position to an upwardly and rearwardly inclinedposition; draft links pivoted at their forward ends to the front wheelassembly and pivoted at their rear ends to the frame; a dump bodysupported for movement longitudinally on the frame to occupy a foresubstantially horizontal position when the frame is in a correspondingposition, and an aft position when the frame is in the aforesaidinclined position; a pair of hydraulic jacks pivoted at one of theirends to the frame and pivoted at their other ends to the draft links,said jacks operating to exert a lifting force on the frame therebycausing operation of the draft links to produce relative approachingmovement of said wheel assemblies whereby the frame is swung to saidinclined position; control links pivoted at their forward ends to thedraft links and at their rear ends to the dump body, the control linksoperating under approaching movement of said wheel assem blies to moveand yet limit the dump body to a predetermined aft position, andoperating under movement of said wheel assemblies away from each otherto restore the dump body to said fore position; a tail gate pivoted onthe rear end of the dump body to occupy an open position or a closedposition according as the dump body occupies the aft position or saidforward position; latching means for the tail gate; and mechanismoperable by movement of the dump body to the aft position for actuatingthe latching means to release the tail gate, and operable by movement ofthe dump body to said fore position for actuating the latching means tolatch the tail gate.

7. In a dump truck having a rear wheel assembly; a frame pivoted on saidassembly for vertical tilting movement from a substantially horizontalposition to an upwardly and rearwardly inclined position; a dump bodysupported for rolling movement on the frame to occupy a fore positionwhen the frame is in said horizontal position, and an aft position whenthe frame is in said inclined position; a first means for moving theframe to said inclined position; a second means operable by the firstmeans for moving the dump body to said fore position or said aftposition according as the frame occupies said horizontal position orsaid inclined position; a tail gate pivoted on the dump body to occupyan open position or a closed position according as the dump bodyoccupies the aft position or the fore position; latch pins on said gate;keepers onthe dump body; latch hooks movable on the dump body to occupya gate latching position in'which they secure said pins in the keepers,a gatereleasing position in which they disengage said -pins; membersmovable lengthwise on the dump body in "one direction or the "other formoving the latch hooks lever fixed to the shaft; an abutment so fixed onthe frame that with movement of the dump body to the aft position on thefore position the lever will be moved by the abutment to rotate theshaft in one direction or the other and thus actuate the members to movethe latch hooks to gate releasing position or gate latching position anda spring associated with the shaft for urging the lever to one side orthe other of a dead center position to maintain the latch hooks inlatching or releasing position after once being moved thereto.

8. A dump truck, including: a front wheel assembly; a rear wheelassembly; a frame separate from the front Wheel assembly and pivoted onthe rear wheel assembly for vertical tilting movement from asubstantially horizontal position to an upwardly and rearwardly inclinedposition; draft links pivoted at their forward ends to the front wheelassembly and pivoted at their rear. ends to the frame; a dump bodysupported for movement longitudinally on the frame to occupy a foresubstantially horizontal position when the frame is in a correspondingposi tion, and an aft position when the frame is in the aforesaidinclined position; mechanism connected between the frame and the draftlinks, and arranged to exert a lifting force on the frame therebycausing operation of the draft links to produce relative approachingmovement of said wheel assemblies whereby the frame is swung to saidinclined position; and control links pivoted at their forward ends tothe draft links and at their rear ends to the dump body, the controllinks operating under approaching movement of said wheel assemblies tomove and yet limit the dump body to a predetermined aft position, andoperating under movement of said wheel assemblies away from each otherto restore the dump body to said fore position.

9. A dump truck as embodied in claim 8, wherein means is provided bywhich the control links are adjustable in relation to the dump body soas to vary the fore and aft positions of the dump body on the frame.

10. A dump truck, including: a front wheel assembly; a rear wheelassembly; a frame separate from the front wheel assembly and pivoted onthe rear wheel assembly for vertical tilting movement from asubstantially horizontal position to an upwardly and rearwardly inclinedposition; draft links pivoted at their forward ends to the front wheelassembly and pivoted at their rear ends to the frame; a dump bodysupported for movement longitudinally on the frame to occupy a foresubstantially horizontal position when the frame is in a correspondingposition, and an aft position when the frame is in the aforesaidinclined position; mechanism connected between the frame and the draftlinks, and arranged to exert a lifting force on the frame therebycausing operation of the draft links to produce relative approachingmovement of said wheel assemblies whereby the frame is swung to saidinclined position; control links pivoted at their forward ends to thedraft links and at their rear ends to the dump body, the control linksoperating under approaching movement of said wheel assemblies to moveand yet limit the dump body to a predetermined aft position, andoperating under movement of said wheel assemblies away from each otherto restore the dump body to said fore position; a tail gate pivoted onthe rear end of the dump body to occupy an open position or a closedposition according as the dump body occupies the aft position or saidforward position; latching means for the tail gate; and mechanismoperable by movement of the dump body to the aft position for actuatingthe latching means to release the tail gate, and operable by movement ofthe dump body to said fore position for actuating the latching means tolatch the tail gate.

11. A dump truck as embodied in claim 1 wherein means is provided to soadjust the last-mentioned means 2,8 1 5,980 9 10 that the fore and aftpositions of the dump body on the References Cited in the file of thispatent frame can be varied. T E TE S 12. In a dump truck as embodied inclaim 7, wherein UNITED S AT S PA NT each member is in two sections; anda yieidable connec- 11755303 Anthony 22, 1930 tion between said sectionsfor urging them toward each 5 13831472 Bjlrrett 1932 Omen 2,621,814Lisota Dec. 16, 1952 2,628,126 Black Feb. 10, 1953 2,696,404 Wallin Dec.7, 1954

